fix(recording): support long room tokens for uploads

[pollychen-lab]

Summary

Keep recording upload app-config keys within Nextcloud's 64-character limit when a conversation uses a long room token.

Root cause

The upload key combines the recupload/ prefix, room token, separator, and a 40-character SHA-1 filename hash. A maximum-length 30-character room token produces an 81-character key, causing chunked upload setup to fail.

Changes

• Size the filename hash according to the remaining app-config key space.
• Preserve the full SHA-1 hash for normal room tokens.
• Add regression coverage for both the existing short-token case and the maximum 30-character token.

At the maximum token length, the filename hash retains 23 hexadecimal characters (92 bits).

Validation

• PHP 8.3 syntax checks for both changed files
• Nextcloud PHP coding-standard check
• Boundary checks for short and maximum-length room tokens
• git diff --check

Fixes #18458

[nickvergessen]

• As per our AI policy, you need to expose the used AI model on commit: https://github.com/nextcloud/.github/blob/master/AI_POLICY.md#disclosure
• Also the communication (PR description) should be manual and you simply replaced the used template with your AI block: https://github.com/nextcloud/.github/blob/master/AI_POLICY.md#human-written-communication
• AI should not be used to work on "good first issues": https://github.com/nextcloud/.github/blob/master/AI_POLICY.md#beginner-issues

[github-actions]

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